This invention relates to sound reduction for turbines for use with paint-spraying equipment, particularly non-bleeder air atomization assisted paint spray guns. In such systems having air supplied from a portable turbine, when the gun is not triggered (shutting off atomization air) means must ordinarily be provided to dump or bleed air from the turbine (or other measures taken) to protect the turbine from over-speeding and over-heating due to the blocked outlet. One approach is to provide a bleed-air discharge from the turbine at all times to prevent these undesirable results. However, using the bleed air approach also introduces a complication of introducing an additional source of relatively high frequency noise resulting from the restriction associated with the bleed-air orifice.
The present invention is directed to overcoming this shortcoming by reducing bleed-air noise associated with turbines for use with non-bleeder type paint spray guns, for example, HVLP or LVLP type spray guns.